Can a woman be expected to work just as fast as a man?

Hey so I don't know if this is the right place for this I just don't know what to do right now. I am a F age 26 for context I am of relatively normal hight for a woman of my age and weights about 110 this will become important I work stocking at a grocery store(the only female in this specific department) my boss will occasionally make comments when he sees me struggling pulling something heavy onto the floor about how I need to gain muscle the few times I admitted defeat and said I can't pull this or lift this he'll make a comment about "oh don't give me that your a weak girl stuff you can do it" always made me kinda angry cause no no I can't I'm not as strong. but recently they are coming at us hard and are now timing the items we take onto the floor how long it takes for us to work a certain number and when I raised concerns cause I'm already pushing myself cause that's just the time of worker I am he looked me in my eyes and said "if I can do this in this amount of time you should be able to as well." And that struck me cause I'm not as strong as a man. am I bad employee or is he being sexist?